Shear bumper

ABSTRACT

There is disclosed herein a pair of shears comprising forwardly projecting blades pivotally secured together by a bolt means. Handle portions projecting rearwardly of the pivot for opening and closing movements include means providing an angled surface associated with each handle, the surfaces abutting when the shears are closed. By means of the angled surfaces, the closing force of the shears is absorbed by flexing of the handles perpendicular to the closing movement, the flexing forces being distributed to resilient means disposed at the pivotal mounting of the blades and outwardly to the blades.

United States Patent 1191 Davis Nov. 12, 1974 [54] SHEAR BUMPER 2,645,850 7/l953 Sejman .1 30/268 X [75] Inventor. Robert T. Davis, K1rtland, Ohio Primary Exammer Al Lawrence Smim [73] Assignee: True Temper Corporation, Assistant Examiner-l C. Peters Cleveland, Ohio 22 Filed: Sept. 24, 1973 [57] ABSTRACT There is disclosed herein a pair of shears comprising [21] Appl- 400,010 forwardly projecting blades pivot-ally secured together by a bolt means. Handle portions projecting rear- 52 US. (:1. 30/271 Werdly efthe Pivot for Opening and closing movements 51 Int. Cl B26b 13/00 ihehlde mednS Providing an angled surface usseeimed [58] Field 61 Search 30/254, 266, 268, 271, with eeeh handle, the Surfhees abutting when the V 30 2 9 shears are closed. By means of the angled surfaces, the closing force of the shears is absorbed by flexing of 5 References Cited the handles perpendicular to the closing movement, UNITED STATES PATENTS the flexing forces being distributed to resilient means 2 010576 8/1935 whyte 30/27 X disposed at the pwotal mounting of the blades and 210593074 10 1936 Whyte 30 271 outwardly to the blade 2,629,170 2/1953 Howell 30/271 X 7 Claims, 7 Drawing Figures SHEAR BUMPER This invention relates to means for absorbing the closing impact shock of a pair of shears and relates specifically to hedge shears or similar shearing devices adapted to be operated manually by two handles and closed with substantial forcefulness.

Conventional shears of the type referred to are commonly limited in their closing movements by projections or bumpers of the handle portions which lie in the same plane and have flat abutting surfaces which strike each other with considerable impact each time a cutting or closing motion is made. This results in constant and repeated shocks to the wrists, forearms, and shoulders of the user which are very tiring. Additionally, the bumping surfaces are usually made of steel and create considerable noise which is annoying and, in itself, a cause of fatigue. Known means for alleviating this problem comprise special rubber bumpers, spring biased plungers for contacting one of the handles, a leaf type spring having a portion adapted to be disposed between the shear bumpers, and providing V-shaped bumpers and bifurcating them to afford a shock absorbing flexibility. All of these means are objectionable in that they call for the expense of added parts or expensive machining and, further, all absorption of the impact shock is substantially concentrated at one point generally in the plane of the shear closing movement.

The present invention is directed to a shock absorbing means for a pair of shears comprising angled mating surfaces associated with'the handle portions adapted to dissipate the shock of the closing force in a flexing action of the handles and blades in the direction perpendicular to the closing movement.

The general object of the present invention is to provide improved shock absorbing means for a pair of heavy, two-handed shears.

Still another object of the invention is to provide such a shock absorbing means which will cause the shock to be absorbed in planes perpendicular to the closing movement of the shears.

Still another object of the invention is to provide a shock absorbing shear bumper having the above features and characteristics wherein absorption of the shock is distributed outwardly along the handles and blades in either direction from the actual bumper device.

A still further object of the invention is to provide shear bumpers wherein a substantial portion of the shock of closing movement is absorbed at the pivot point of the blade and by the inherent resilience of the blades themselves.

Other objects of the invention and a number of the advantages thereof will be clearly understood from the following description of one embodiment of the invention as shown in the accompanying drawings, in which said drawings:

FIG. 1 is a top plan view of a pair of hedge type shears incorporating the shear bumpers of this invention;

FIG. 2 is a side elevation of the shears of FIG. 1;

FIG. 3 is an enlarged sectional detail taken along the line 33 of FIG. 1;

FIG. 4 is a transverse section taken along the line 4--4 of FIG. 1 showing the shear bumpers in closed position and under impact load;

FIG. 5 is a section similar to FIG. 4 showing the shear bumpers in the open position;

FIG. 6 is a greatly enlarged detail in section showing the relative positions of the angled contact surfaces of the bumpers under impact load; and

FIG. 7 is a greatly enlarged detail similar to FIG. 6 showing the relative positions of the angled contact surfaces of the bumpers when the shears are closed and at rest.

Referring now to the drawings in all of which like parts are designated by like reference numerals, the hedge shears herein illustrated comprise upper and lower blades 10 and 11, respectively, pivotally connected to each other by a pivot bolt 12. The blades 10 and 11 have integral handle portions 13 and 14, respectively, said handle portions being provided with handgrips 15 and 16, respectively.

As shown in FIG. 3, the pivot bolt 12 has an enlarged upper head 18 and a downwardly projecting shank 19 which projects through suitable apertures 20 and 21 in the blades 10 and 11, respectively. Resilient biasing means 22 is provided between the enlarged head 18 and the upper surface of the upper blade 10, and the entire blade assembly is completed by a conventional nut 23 having a thread fitted engagement with the lower end of the shank 19. The resilient biasing means may take any suitable form and as herein'illustrated comprises a sheet spring washer which is curved in transverse section whereby to resiliently resist tightening of the nut 23. It will also be noted in FIGS. 2 and 3 that the blades 10 and 11 are relatively bowed away from each other in the center, as indicated at 10' and 11', respectively, in such manner asto place the blades under tension with respect to each other and insure continuous contact between the cutting edges as the shears close. v

At a position substantially rearwardly of the pivot bolt 12, the handle portions 13 and 14 are provided with abruptly upwardly projecting steps 25 and 26, respectively. Rearwardly of said steps, the handle portions 13 and 14 are provided with laterally inwardly projecting stops or bumpers 27 and 28, respectively, which are disposed in a common transverse plane. It will be readily understood that when the shears are closed the bumpers 27 and 28 abut each other and stop the closing movement.

As illustrated in FIGS. 4-6, the bumper 27 associated with the upper blade 10 is provided with a backwardly undercut, angled contact surface 29 whereas the bumper 28 associated with the lower blade 11 is provided with a forwardly angled contact surface 30 disposed at the same angle as the surface 29. Thus, it will be readily seen that when the shears are closed, the angled surfaces 29 and 30 meet flatwise at an angle to the closing movement.

When the shears are slightly open as shown in FIG. 5 with the bumpers 27 and 28 separated, said bumpers are disposed in the same plane. Even with the shears closed, the bumpers remain in the same plane when the shears are at rest; that is, when the bumpers are not being forced together as shown in FIG. 7. However, during the clipping movement of the shears, the bumpers 27 and 28 are brought together sharply and are repeatedly subjected to substantial impact stress. This stress causes the angled surfaces 29 and 30 to be forced against each other, the angle thereof resulting in each bumper camming the other in a direction perpendicular to the direction of closing movement. As a result, the handle portion 13 associated with the upper blade 10, flexes slightly upwardlyand the handle portion associated with the lower blade 11 flexes slightly in the downward direction. Referring to FIGS. 4 and 6, the result of the bumpers engaging each other with substantial force is symbolically illustrated by the arrows F1 and F2which represent the closing force and direction of the blades, the arrow F3 which represents the upward force and flexing of the handle portion 13 and the arrow F4 which represents the downward force and flexing of the handle portion 14. The force and direction arrows F3 and F4 are also indicated on FIG. 2 to further clarify this action.

It will be readily seen that upward flexing of the bandle portion 13 causes a corresponding upward flexing or force on the upper blade 10 at the pivot bolt 12. This force is designated by the arrow F7 in FIG. 2 and is most immediately received by the resilient biasing means 22 below the head 18 of the pivot bolt 12. The downward flexing of the handle portion 14 causes a corresponding downwardly flexing of the lower blade 11 against the nut 23. This force is illustrated by the arrow F8. Thus, the forces F3 and F4 exerted at the shear bumpers 27 and 28 tend to separate the blades 10 and 11 at the pivot bolt 12 and compress the resilient biasing means 22. However, it will be readily seen that the forces F7 and F8 act oppositely against each other as indicated by the arrows F and F6 in FIG. 2 whereby the bolt-washer-nut assembly provides fulcrum points about which the forwardly projecting portions of the blades and 11 are tilted downwardly and upwardly respectively against each other. The outermost tips of the blades are, therefore, urged even more tightly together as indicated by the arrows F9 and F10 while the medial portions of the blades at the bows 10' and 11' are caused to flex inwardly as indicated by the arrows F11 and F12.

As a result of the above construction, the impact shock of the closing ofthe shears is distributed to a very large extent throughout the blades, handle portion and handgrip in the direction perpendicular to the closing movement with the primary shock absorbing means comprising the resilient biasing means 22 at the pivot bolt 12 and the inherent spring action of the bowed and slightly separated blades 10 and 11 in the closed position. This substantially eliminates the closing shock of the shears to the wrists, arms, and shoulders of the user thus making the tool more comfortable to use and usable over longer periods without undue fatigue.

It will be understood that many changes in the details of the invention as herein described and illustrated may be made without, however, departing from the spirit thereof or the scope of the appended claims.

I claim:

1. In a pair of shears having forwardly projecting blades and rearwardly projecting two-handed gripping means for opening and closing movements of the .blades in a plane, pivot means connecting said blades including resilient means resiliently urging said blades toward each other at said pivot means; each of said gripping means having a stop rigidly fixed with respect thereto and adapted to abut the stop of the other gripping means to limit the closing movement of said blades; said stops having surfaces adapted to abut flatwise when the shears are closed, said surfaces being angled whereby said stops partially overlap in the direc- 4 tion of closing and, in response to closing impact shock, flex the associated gripping means in opposite directions away from each other perpendicular to the direction of closing, against the bias of said resilient means, toabsorb the closing shock. I

2. In a pair of shears having forwardly projecting blades connected by pivot meansadjacent to the rearwardly directed ends thereof, each blade having a handle rigidly secured thereto rearwardly of said pivot means whereby said shears are adapted for two-handed opening and closing movements; said pivot means including resilient means resiliently urging said blades toward each other at said pivot means; each said handle having a stop rigidly fixed with respect thereto disposed rearwardly of said pivot means and adapted to abut the stop of the other gripping means to limit the closing movement of said blades; and stops having surfaces adapted to abut flatwise when the shears are closed, said'surfaces being angled whereby said stops partially overlap in the direction of closing and, in response to closing impact shock, flex the associated handles in opposite directions away from each other perpendicular to the direction of closing movement, said stops and said surfaces affording unrestrained flexing of said handles in said opposite perpendicular directions against the bias of said resilient means at all times, to absorb the closing shock.

3. In a pair of shears as set forth in claim 2: said blades being flexible and outwardly bowed with respect to each other whereby medial portions of said blades are spaced apart slightly in the closed position, the ends of the blades engaging each other; said pivot means providing fulcrums whereby flexing of said handles away from each other rearwardly of saidpivot means causes said blades to flex toward each other in a plane perpendicular'to the direction of closing movement forwardly of said pivot means whereby a portion of the closing impact shock is absorbed bysaid blades.

4. In a pair of shears as set forth in claim 3: said pivot means including a shank member projecting through aligned apertures in said blades, one end of said shank member having means providing an'enlargement; said resilient means comprising a spring disposed between said enlargement and the outer surface of the adjacent of said blades.

5. In a pair of hedge type shears, upper and lower overlapping blades connected by a pivot bolt for lateral opening and closing movements; said blades each having a rearwardly projecting, integral handle portion disposed rearwardly of said pivot bolt; at least one of said blades being centrally bowed away from the other said blade lengthwise of said blades; said pivot bolt having an enlarged upper head and a spring washer compressively disposed beneath said head resiliently biasing said blades together in a direction perpendicular to the direction of blade closing; said handle portions having inwardly facing, integral stops which abut and limit the closing movement of said shears; said stops including means for camming said handles apart in directions perpendicular to the handle closing movement, said camming means affording unrestrained flexing of said handles in said perpendicular directions against the bias of said spring at all times in response to the closing impact shock whereby said blades are flexed toward each other forwardly of said pivot bolt thereby absorbing the impact shock and distributing it throughout said handles, spring, and blades.

6. In a pair of shears comprising upper and lower blades each having a rearwardly projecting gripping means for opening and closing movements of the blade in a plane; pivot means connecting said blades includingresilient means resiliently urging said blades toward eachother at said pivot means; each of said gripping means having a stop rigidly fixed with respect thereto and adapted to abut the stop of the other gripping means to limit the closing movements of said blades; at least one of said stops having abutting surface means inclined with respect to the plane of closing movement of the shears; the other said stop having abutting surface means for engaging said first mentioned abutting face means for receiving the impact shock. 

1. In a pair of shears having forwardly projecting blades and rearwardly projecting two-handed gripping means for opening and closing movements of the blades in a plane, pivot means connecting said blades including resilient means resiliently urging said blades toward each other at said pivot means; each of said gripping means having a stop rigidly fixed with respect thereto and adapted to abut the stop of the other gripping means to limit the closing movement of said blades; said stops having surfaces adapted to abut flatwise when the shears are closed, said surfaces being angled whereby said stops partially overlap in the direction of closing and, in response to closing impact shock, flex the associated gripping means in opposite directions away from each other perpendicular to the direction of closing, against the bias of said resilient means, to absorb the closing shock.
 1. In a pair of shears having forwardly projecting blades and rearwardly projecting two-handed gripping means for opening and closing movements of the blades in a plane, pivot means connecting said blades including resilient means resiliently urging said blades toward each other at said pivot means; each of said gripping means having a stop rigidly fixed with respect thereto and adapted to abut the stop of the other gripping means to limit the closing movement of said blades; said stops having surfaces adapted to abut flatwise when the shears are closed, said surfaces being angled whereby said stops partially overlap in the direction of closing and, in response to closing impact shock, flex the associated gripping means in opposite directions away from each other perpendicular to the direction of closing, against the bias of said resilient means, to absorb the closing shock.
 2. In a pair of shears having forwardly projecting blades connected by pivot means adjacent to the rearwardly directed ends thereof, each blade having a handle rigidly secured thereto rearwardly of said pivot means whereby said shears are adapted for two-handed opening and closing movements; said pivot means including resilient means resiliently urging said blades toward each other at said pivot means; each said handle having a stop rigidly fixed with respect thereto disposed rearwardly of said pivot means and adapted to abut the stop of the other gripping means to limit the closing movement of said blades; And stops having surfaces adapted to abut flatwise when the shears are closed, said surfaces being angled whereby said stops partially overlap in the direction of closing and, in response to closing impact shock, flex the associated handles in opposite directions away from each other perpendicular to the direction of closing movement, said stops and said surfaces affording unrestrained flexing of said handles in said opposite perpendicular directions against the bias of said resilient means at all times, to absorb the closing shock.
 3. In a pair of shears as set forth in claim 2: said blades being flexible and outwardly bowed with respect to each other whereby medial portions of said blades are spaced apart slightly in the closed position, the ends of the blades engaging each other; said pivot means providing fulcrums whereby flexing of said handles away from each other rearwardly of said pivot means causes said blades to flex toward each other in a plane perpendicular to the direction of closing movement forwardly of said pivot means whereby a portion of the closing impact shock is absorbed by said blades.
 4. In a pair of shears as set forth in claim 3: said pivot means including a shank member projecting through aligned apertures in said blades, one end of said shank member having means providing an enlargement; said resilient means comprising a spring disposed between said enlargement and the outer surface of the adjacent of said blades.
 5. In a pair of hedge type shears, upper and lower overlapping blades connected by a pivot bolt for lateral opening and closing movements; said blades each having a rearwardly projecting, integral handle portion disposed rearwardly of said pivot bolt; at least one of said blades being centrally bowed away from the other said blade lengthwise of said blades; said pivot bolt having an enlarged upper head and a spring washer compressively disposed beneath said head resiliently biasing said blades together in a direction perpendicular to the direction of blade closing; said handle portions having inwardly facing, integral stops which abut and limit the closing movement of said shears; said stops including means for camming said handles apart in directions perpendicular to the handle closing movement, said camming means affording unrestrained flexing of said handles in said perpendicular directions against the bias of said spring at all times in response to the closing impact shock whereby said blades are flexed toward each other forwardly of said pivot bolt thereby absorbing the impact shock and distributing it throughout said handles, spring, and blades.
 7. In a pair of shears as set forth in claim 6: said abutting surface means comprising the sole abutment surface means for receiving the impact shock. 